Oral anticoagulation therapy using warfarin is given to over 4 million outpatients each year to prevent thrombotic complications associated with prosthetic heart valves, deep venous thrombosis, atrial fibrillation, post myocardial infarction, and chronic heart failure. Frequent prothrombin time (PT) measurements are necessary to monitor warfarin therapy to prevent excessive or subtherapeutic dosing. This is necessary sine the warfarin dosage varies considerably between patients and even within the same patient. Using current approaches this process of monitoring and efficiently managing these patients is complex, inefficient and time intensive. Recent advances in computer technology such as multi-media systems, expert systems, and CD-ROM may be useful in improving the management of the anticoagulated patient. An ideal application of the above technology is in the area of outpatient anticoagulation therapy Instruments for measuring the PT at patient side are currently available. This opens the possibility of obtaining PT information in the physician's office or the patient performing this test at home. A method for managing dosage decisions is critical, and in the case of home use an efficient method for communicating PT information, and hemorrhagic or thrombotic symptoms back to the physician needs to be in place to assure proper management of the warfarin therapy. Using available validated systems for warfarin dosage adjustments, utilizing a multi-media approach to educating patients and clinicians, and creating in expert system/communications software would assist in streamlining outpatient anticoagulation.